Priggishness means self-righteous, performative morality. Can you give an example of this that is normal for US right-wingers? They certainly have plenty of daft ideas (e.g. anti-vax), but I haven't seen right-wingers being priggish about them. Priggish would be positioning themselves as superior people for living in an unvaccinated neighborhood or working for an anti-vax employer, or proclaiming that they will not date a vaccinated person, or vaccinating their baby in secret while posting the opposite on social media, or cancelling a public figure who gets outed as vaccinated, etc.